There is little doubt that large quantities of mercury were utilized by the precious metals mines which functioned along the Carson River, Nevada from the 1850's to the 1900's. As a result mercury has been located in old mine dumps; in river sediment and in wild fish and game in such quantities throughout the river site that the area is listed as a "Superfund" site. However, no information is available concerning human health effects of this pollution. The major goal of the proposed study is to obtain samples of blood from the population within the site and determine if these show elevated levels of mercury (total and methylmercury). At the same time a detailed questionnaire will be administered to determine the individual's potential contact with the mercury and to uncover potential mercury related health problems. Any correlation between these blood data and residence times at the Carson River; recreational contact with the river; consumption of fish/game from the river; or the population's health will be calculated. In addition, an historical survey of the incidence of potential mercury related health effects will be undertaken by examination of the birth records to determine if the site shows an increased incidence of complications of pregnancy. This study will be the first epidemiological survey of humans living within the Carson River Superfund Site and will indicate whether health problems exist and if so where these might be most significant.